1. Field of the Invention
This invention relates to a piezoelectric actuator in which expansible piezoelectric elements formed of, for example, piezoelectric ceramic or the like are employed. The piezoelectric actuator of this type is used as a vibration source, for example, in a vibrator, or as a device for controlling an object to be in an upper limit position and a lower limit position.
2. Prior Art
Heretofore, a piezoelectric actuator of this type has employed a structure in which expansible piezoelectric ceramics are laminated in multilayers, and the respective piezoelectric ceramics are expanded/contracted by voltage supplied thereto, so that such expansions/contractions are accumulated to expand or contract the whole multilayer structure in the laminating direction.
In the above piezoelectric actuator, the expanding amount of the whole actuator is obtained by an increase in width dimension when each piezoelectric ceramic is contracted. However, since the increase in width dimension due to contraction of each piezoelectric ceramic is very small, a sufficient amount of expansion of the whole actuator is difficult to obtain.